[translator] move main function from compiler-rt

clang can work with double main(void)

Author: jauhien

examples/plot.ks

@@ -1 +1 @@
-def run() mandel(-2.3, -1.3, 0.05, 0.07);
+def main() mandel(-2.3, -1.3, 0.05, 0.07);

translator/compiler-rt/compiler-rt.c

@@ -1,7 +1,5 @@
 #include <stdio.h>
 
-extern double run();
-
 double putchard(double x) {
    putchar(x);
    return x;
@@ -11,7 +9,3 @@ double printd(double x) {
    printf("> %f <", x);
    return x;
 }
-
-int main(int arc, char** argv) {
-   return run();
-}